1. Field of the Invention
The present invention relates to a light source for a display device.
2. Description of the Related Art
Display devices used in image displays, such as television receivers and computer monitors, are classified as self-luminescence, and light receiving displays. Self-luminance displays include light emitting diodes (LEDs), electroluminescence (EL) devices, vacuum fluorescent displays (VFDs), field emission displays (FEDs), plasma display panels (PDPs), etc.,: Light receiving displays include liquid crystal displays (LCDs).
An LCD includes a pair of panels individually having electrodes on their inner surfaces, and a dielectric anisotropy liquid crystal layer interposed between the panels. In the LCD, varying of the voltage difference between the field generating electrodes, changes the transmittance of light passing through the LCD. Therefore, desired images are obtained by controlling the voltage difference between the electrodes.
In the LCD, the light may be a natural light or an artificial light emitted from a light source separately used with the LCD. For example, a backlight device may be used to provide artificial light to the LCD. The backlight device may use light emitting diodes (LEDs) or fluorescent lamps, such as cold cathode fluorescent lamps (CCFLs), external electrode fluorescent lamps (EEFLs), etc., as the light source. LEDs are popular because they are eco-friendly since they do not use mercury (Hg) and they have a longer work life than most other light sources. However, typical LEDs emit light directly upward and the light does not spread or disperse.